Researchers at Harvard University and Harvard Medical School conducted an experiment that indicates that dreaming during non-REM (rapid eye movement) sleep after performing a difficult task helps participants complete the activity more successfully after waking. (Scientists have only observed learning during non-REM sleep and not during REM sleep.) The researchers’ results also indicate that just thinking about the activity after first performing it does not help in later attempts to complete the task. These findings support earlier research indicating that sleep improves memory and learning.

“Task-related dreams may get triggered by the sleeping brain’s attempt to consolidate challenging new information and to figure out how to use it,” Dr. Robert Stickgold, study co-author, told ScienceNews about their results.

Researchers recruited 99 college students between the ages of 18 and 30 to participate in the study. For the experiment, the volunteers spent 60 minutes working individually to solve a 3-D virtual maze on a computer. During the activity, the participants performed several trials, and started the maze at a different location each time. In addition, while solving the maze, the participants were told to memorize the location of a specific tree’s location in the puzzle.

After spending an hour working on the maze, the participants were given a five-hour break. Half of the participants were instructed to take a nap, and the other half of participants were told to take part in quiet activities, such as reading or watching a video. For the nap group, the researchers fitted each participant with scalp sensors to monitor their brain activity while asleep. In addition, members of the napping group were asked about the content of their dreams just before they fell asleep, one minute after non-REM sleep, and at the end of their nap. Of the 50 participants in the nap group, four recounted dreaming about the maze activity. For the participants in the quiet activity group, each members was asked what they were thinking about at the beginning, middle, and end of the activity period.

After a lunch break and another period of quiet activity in which both groups of participants took part, the volunteers were asked to repeat the virtual maze activity. Those participants in the nap group who recalled dreaming about the maze in their sleep performed better the second time around in the maze activity and also found the tree that they had been told to remember quicker than other participants. All of the members of the nap group had been relatively unsuccessful in their attempts to complete the maze in the earlier session. The study authors suggest that tasks that are difficult and/or important to complete provoke memory processes in the brain required for learning to activate during sleep.

The scientists plan to continue their research into the connection between dreaming and learning. Future research plans include having study participants navigate through a more “exciting” virtual maze. The researchers are also interested in determining whether participants that have REM dreams about the maze during a normal full night’s sleep are able to better navigate the maze the next day.

The results of the scientists’ research were published in the April 22, 2010 online edition of the journal Current Biology. Study authors included Erin J. Wamsley, Matthew Tucker, Jessica D. Payne, Joseph A. Benavides, and Robert Stickgold.